Hunter extension redirect works for signed-out users

The problem

The /hunter/firebase redirect was inside an authenticate block,
so signed-out users hit the Devise sign-in page directly instead of
landing on the proper Hunter onboarding flow.

The fix

Moved the redirect outside the authenticate block. Anonymous users
now go to /hunter/creatives, which itself requires sign-in — but
Devise bounces them back to the right destination after login.